window.onload = function()
{
    var canvas = document.getElementById( 'canvas' );
    if ( !canvas.getContext )
    {
        return;
    }
    var context = canvas.getContext( '2d' );
        
    context.setTransform( 1, 1, 0.5, 2, 30, 30);

    context.fillRect( 20, 20, 50, 50 );
}